What's the story

Producing a novel should be fun even though it's difficult, says writer Robert Harris. And while there are guides to help you along the way, fundamentally it's all down to you.

Writing a novel - unlike operating a piece of heavy machinery, say, or cooking a chicken - is not a skill that can be taught. There is no standard way of doing it, just as there is no means of telling, while you're doing it, whether you're doing it well or badly. And merely because you've done it well once doesn't mean you can do it well again. The whole process is a mystery, devoid of rules or fairness.

That doesn't mean that guides like this are without value. On the contrary. Having the urge to write a novel, especially if you've yet to be published, is like having a medical condition impossible to mention in polite company - it's a relief simply to know there are fellow-sufferers out there.

In the 20 years that I've been writing fiction, three pieces of published wisdom, each offered by an eminent American novelist, have helped me along. The first was from John Irving, who maintains that any writer who embarks on a novel without knowing how it is going to end is a fool and a knave. A novel, he argues, recounts something that has already happened; therefore you cannot just make it up as you go along. This practical approach had a profound effect on me: indeed, it enabled me to complete my first novel, Fatherland which, in classic rookie fashion, had trailed to a baffled halt somewhere around page 50.

The second was from a 1995 interview with EL Doctorow: "You have to find the voice that allows you to write what you want to write ... It's a writer's dirty little secret that language precedes the intentions." On the face of it, this contradicts Irving ("I don't begin with a plan," insists Doctorow), but actually they are both saying the same thing, which is that the shape and style of a novel is determined by the thought you give it beforehand: that the way you approach your material is at least as important, maybe more important, than the material itself. This process of settling on an angle of attack may take months, even years of frustration and false starts, during which many writers - and certainly most writers' families and friends - believe the author may be going slightly mad.

Have courage, and remember the words of my third authority, Philip Roth, in 2003. "Over the years," he observed, looking back on his career on his 70th birthday, "what you develop is a tolerance for your own crudeness. And patience with your own crap, really. Belief in your crap, which is just 'stay with your crap and it will get better, and come back every day and keep going'."

To these three dictums, Polonius-like, I can add a few more. Don't try to write too much in a single session. One thousand words a day is quite enough. Stop after about four or five hours. Remember that most writing is done in the subconscious ("the boys in the basement," as Stephen King calls his unseen helpers) and that inspiration is only a posh word for ideas. Pace yourself, get some recreation, avoid tiring yourself out. Cut your manuscript ruthlessly but never throw anything away: it's amazing how often a discarded scene or description, which wouldn't fit in one place, will work perfectly later. Resist the temptation to show off your research (one of Tom Stoppard's maxims is, Just because it's true doesn't mean it's interesting). Be economical: Noel Coward's definition of good writing was the art of conveying something in as few words as possible .

Finally: enjoy yourself. "A writer who hates the actual writing,' Raymond Chandler once observed, "who gets no joy out of the creation of magic by words, to me is simply not a writer at all." That's the essence of being a novelist, and if you don't feel a surge of recognition on reading those words, it might be advisable to do something else.

· Robert Harris is the author of several bestselling historical novels, including Fatherland, Archangel and Pompeii. His most recent book is the political thriller The Ghost (Arrow Books).